Steady State Speed vs Fuel Economy results

Discussion in 'General' started by seftonm, Mar 22, 2014.

  1. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    I'm sure there's a giant difference between the two. Myself, I'd take the Miata with the retractable hardtop , to make things a bit more serene at speed.
     
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  2. RoadWarrior222

    RoadWarrior222 rockit serjun

    I'd take one of these... http://shop.autokonexion.com/product.sc?productId=38&categoryId=19

    But for that money I'd want to do it myself, possibly with a trunk lid delete for hatchback, and more tumblehome, and 2/3 rear height kammback shape, and a couple of HCH pancake motors in series with a 30HP Kubota diesel... ... uh sorry, got carried away, anyone got an old Miata with a blown motor?
     
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  3. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Bill:

    They take it tomorrow and I was thinking about doing a quick 60 mph run with the top down this afternoon. I have way to much work to do for the #RamTarget40 drive beginning on Thursday to do a complete 50 - 70 mph set. :(

    Wayne
     
  4. BillLin

    BillLin PV solar, geothermal HVAC, hybrids and electrics

    Hi Wayne,

    No worries. I appreciate the thought.

    Good luck with the Ram, not that you need it. :)

    Cheers,
    Bill
     
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  5. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi All:

    The 2014 RAM 3500 Big Horn Crew Cab 4X4 with 17” on/off-road DRW and the 6.7L Cummins (3.73 rear end) Speed vs. FE is complete.

    [​IMG]

    From the calibration drive, it was found the aFCD under reports actual by 4.9 percent.

    The calculated 1,490 RPM@60 mph ended up at 1,550 RPM at the same.

    No wind and temps from 64 to 66 degrees F for the NB and SB runs averaged at each speed and multiplied by the offset.

    What is unique here is the graph gives us a look into the future when the 3/4 and 1-ton trucks will have EPA results posted on their Monroneys.

    I am guessing here but if this 2014 RAM 3500 were EPA rated, it would be 20 to 21 mpg highway.

    The 20 to 21 mpg estimate arises from the fact this is a DRW vehicle with On/Off-road Nokian tires. EPA estimates are based off of the most popular setup (SRW and 18" road tires) so I would expect another 1 mpg added to the highway estimate at the 67.5 to 70 mph cross over point of 20.5 to 19.5 mpg.

    On the city number, I was moving furniture and household stuff from an apartment to a home about 1-mile away multiple times. After IIRC, 12 RTs, the average was 14.0 mpg or 14.7 mpg actual. This is far worse then the EPA city test as there were 4-point turn within the complex, 5-stops, and nothing over 30 mph from apartment to home. At 14.7 while loaded with 250 to 1,000 pounds of stuff on each trip as described, I would suspect the RAM 3500 4X4 with the 6.7L Cummins to receive a 15 to 16 mpg city rating.

    Combining all of the above, if the 2014 RAM 3500 4X4 with the 6.7L Cummins had a Monroney with EPA estimates embedded, I would guess it may read 15/21/17 mpgUS city/highway/combined.

    Wayne
     
    Last edited: Aug 26, 2014
  6. worthywads

    worthywads Don't Feel Like Satan, I am to AAA

    Did you get data for the eco-diesel Wayne?
     
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  7. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi WW:

    I did not have time before having to turn it in.

    Wayne
     
  8. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi All:

    The 2014 Kia Optima Hybrid EX Speed vs FE graph.

    [​IMG]

    The 39 mpg highway rated EX crossed over at a slightly low 67.8 mpg (linear). Unfortunately the weather window was to short with a 5-10 mph wind from the South (NB and SB runs) and it began to rain during the SB 65 mph and 70 mph runs so I had to cut their distances which in turn left some mpg on the table.

    RPM@60 mph was 1,990 vs. the 1,980 calculated.

    Wayne
     
  9. ALS

    ALS Super Moderator Staff Member

    That Kia Optima definitely needs some work on the top gearing. I think a little more highway gearing would help her out. Dropping her down to 1900 or 1875 rpms at 60 would make a big difference in fuel mileage between sixty and seventy. I wouldn't go much lower than that due to the cars weight.
     
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  10. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    My little 1.8 wheezer turns 2000 RPM at that speed. The Optima should/could be more like 1600-1700 RPM.
     
  11. RedylC94

    RedylC94 Well-Known Member

    Why's that Optima 3-4 mpg below the '13 Sonata hybrid at all speeds?
     
  12. NeilBlanchard

    NeilBlanchard Well-Known Member

    It could be a difference in the CdA of each? Since aero drag is ~75% of the load on the drivetrain at 55MPH and ~87% at 75MPH, it would only take a relatively small difference to account for the FE gap.
     
  13. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi RedylC94:

    Less aero and this is the EX? This was not a good overall imho.

    Wayne
     
  14. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi All:

    Just completed the 2015 Honda Fit EX with the 6-speed stick a few minutes ago.

    [​IMG]

    Wayne
     
  15. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    Curious results compared to mine. It's not as much higher as the ratings suggest. EPA 27/33 vs 29/37. Here we are looking at the highway 33 vs 37 (12% better), but our test results show no improvement at 50 and only 6% above that. Me wonders if they calibrated it to the test better this time around. :/

    [​IMG]
     
    Last edited: Nov 14, 2014
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  16. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi All:

    2014 Nissan Sentra SL with the CVT.

    [​IMG]

    Wayne
     
  17. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi All:

    The 2015 Hyundai Accent GLS sedan I am currently driving.

    [​IMG]

    With temps between 42 and 45 degrees F, I should have added an offset which would increase the above by ~ 5 percent across each point on the graph.

    EPA highway rating of 37 was crossed over at 71.9 mph. A good showing considering the temps. Probably should be rated at about 39 mpg highway vs. the 37 mpg that it is.

    Wayne
     
  18. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi All:

    The 40/38 mpgUS city/highway rated 2015 Toyota Camry Hybrid SE's steady states were completed in atrocious conditions. The deltas on the North-South route with temps in the 20’s and WSW winds at 10 to 20 mph resulted in a poor confidence number.

    The aFCD offset is 0.9623. For the chart, I gave the Camry Hybrid SE 10.0 percent given the temps to match it up to a 70 degree summer temperature.

    [​IMG]

    Do not take this Speed vs FE chart as gospel as it was extensively fit due to those high North-South deltas in poor wintry conditions.

    Wayne
     
  19. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi All:

    30/36 mpgUS city/highway rated 2015 Toyota Yaris SE Speed vs. Fuel Economy graph.

    This is not a representative Speed vs FE graph as temps were -5 to -7 degrees F with 5 to 10 mph winds out of the NW on the Northbound and Southbound circuits.

    The aFCD offset is aFCD display * 0.972.

    [​IMG]

    I will not even get into the fact the Yaris crossed over its 36 mpg highway rating EPA at ~ 54.8 mph, the lowest speed at which the EPA highway crossover occurred that we have ever measured. I cannot come close to creating a temperature offset at these cold temps to match up to a 70 degree day.

    Speedometer error is 2 mph over at 50 mph actual (52 mph displayed) to 1.5 mph over at 70 mph actual (71.5 mph displayed).

    RPM@60 mph was just over 2,600 and created a buzz bomb from 60 mph on up. Rarely does engine noise overcome wind noise above 20 to 30 mph. The Yaris’ engine thanks to that poorly geared and decade out of date 4-speed AT created more noise than wind and the drone was a non-starter.

    Wayne
     
    Last edited: Feb 19, 2015
  20. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    I totally cannot believe they stick with that ancient AT. It seems like they don't really want to compete in the B-class , but still need something below the Corolla for advertising purposes. C'mon, Jan. Give us something a little bit better.

    Still , a Yaris 5MT in warmer weather could give some decent results, I'll wager.
     
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